Elastomeric coatings containing glass bubbles

ABSTRACT

A formulation for surface coating applications, particularly surfaces which are in frequent contact with water and remain water-wet, and/or surfaces of elastomeric and plastic foams, especially foams fabricated from polyethylene and polyurethane resins. The formulation includes a vehicle consisting primarily of a block polymer of styrene/ethylene/butylene/styrene and methylmethacrylate copolymer or related block polymer with lesser degrees of ethylenic unsaturation together with a rubber tackifier, with fillers being provided including particulate colloidal or powdered silicon dioxide, and glass microspheres having an average size of less than about 70 microns. The formulation is such that it is adaptable to be applied by either air pressure spray systems or aerosol packaging techniques.

BACKGROUND OF THE INVENTION

The present invention relates generally to an improved formulation forsurface coating applications, particularly wherein the surfaces to becoated are in frequent contact with water, and additional surfaceroughness is required to increase frictional and anti-slipcharacteristics of the surface. The surface coating formulations of thepresent invention are particularly adapted for providing uniform surfaceroughness or coarseness which enhances frictional, and particularlyanti-slip characteristics on treated surfaces.

In many situations, it is desirable, if not necessary, to provide asurface with enhanced frictional properties, particularly a surfacewhich is roughened sufficiently to provide the desired frictional andanti-slip characteristics. One typical application is for decks ofsurfboards, as well as on surfaces of wind surfing equipment. The recentincrease in popularity of these items as sporting equipment has createdan unusual need for an anti-slip coating which is effective underwater-wet conditions, including a relatively wide range of temperatures.In addition to use in combination with sporting equipment, this materialmay also be used around swimming pools, shower stalls, bathtubs, andother areas where it is desirable to have anti-slip characteristics insurfaces subject to becoming wet with water.

Various types of anti-slip products have been designed in the past, andfrequently in the form of a laminate or thin flexible decal which may beapplied to a surface by pressure-sensitive adhesive or the like. Thepresent formulation, being an organic solvent coating dispersion, may beapplied by either brushing, spraying, or other conventional techniquesto the entire area desired for the coating. The formulation, because ofthe selection of components, is such that spraying may be achieved byair-pressure systems, or alternatively by aerosol packaging.

One unusual feature of this invention is the high degree of anti-slipcharacteristics and properties which are developed in the exposedsurface, particularly under water-wet conditions. While the specificreason for achieving this increase in friction and anti-slip propertiesis unknown, it is believed to have been achieved by the combination ofan elastomeric vehicle with high-strength glass bubbles or spheres.High-strength glass bubbles of generally spherical form are described inU.S. Pat. No. 3,365,315, and are, of course, commercially available. Thevehicle, including the elastomeric components, provides good adhesion tothe surface to which it is being applied, as well as a proper balanceand maintenance of cohesive properties. Specifically, the formulationsof the present invention provide an appropriate adjustment of adhesivestrength to cohesive strength in the finished cured coating. Thus, theformulations of the present invention have been found to be resistant tostripping or peeling, and have been found to achieve the property ofremoval from the surface only upon tearing.

In connection with surfboard enthusiasts, there are demands for varioustypes of anti-slip coating formulations. In certain applications, andfor certain such enthusiasts, it is deemed desirable to have atransparent coating which makes it possible to exhibit any unusualfeature of the natural surface or any unique or colorful design of theartwork available on the surfboard substrate. In others, there may be aneed or desire for applying a certain type of coating as well ascoatings which fluoresce or otherwise glow in the presence ofultraviolet rays of the sun. With each of these various features inmind, the coating formulations of the present invention lend themselvesto modification so as to achieve such results and/or properties, whilestill permitting application by spraying, including both air-pressureand aerosol spraying. The components present in the formulations of thepresent invention are non-clogging, this being due to the utilization ofthe glass bubbles which are small in size and substantially spherical inconfiguration.

In addition to use of these coatings on surfaces which are frequentlysubject to wetting, the materials have application for use on surfacesof elastomeric and plastic foams, especially polyethylene andpolyurethane foams. In particular, closed foams are used for a varietyof purposes and as such, do not permit air to pass readily from one sideto the other. In connection with certain facilities used for athleticpurposes, such as exercise and wrestling mats, these materials have afrequent need of covering or coating with an elastomeric seal-coat withanti-slip properties. It is a desirable feature of any such seal-coat toutilize a coating which bridges the surface pores of the foam withoutproviding significant penetration of the pore structure of the foam. Inthis fashion, saturation of the pores of the foam with the seal-coat isavoided. Such a feature is desirable in that saturation would in certaininstances detract from the padding effect and would further increase theweight of the foam structure, thus providing for added weight, lessresiliency or bounce, and less absorption of impact.

SUMMARY OF THE INVENTION

Therefore, it is a primary object of the present invention to provide animproved coating formulation which has increased frictional andanti-slip properties, and which formulation is capable of being appliedto surfaces by conventional spray techniques, including air pressureand/or aerosol techniques.

It is a further object of the present invention to provide an improvedformulation for coating surfaces which are normally in contact withwater, and wherein the improved frictional and anti-slip characteristicsare retained when used on surfaces which are normally water-wet duringuse.

It is yet a further object of the present invention to provide animproved coating formulation for water-wet surfaces which includes aquantity of high-strength glass bubbles or microspheres in theformulation, and which formulation is capable of surface application byspraying with either air pressure or aerosol packaging techniques.

Other and further objects of the present invention will become apparentto those skilled in the art upon a study of the following specificationand appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiments of the present invention are best expressed interms of the following examples hereinbelow.

EXAMPLE 1

A translucent anti-slip coating composition as follows:

    ______________________________________                                        Material               Parts by Weight                                        ______________________________________                                        Solvent mixture.sup.(1)                                                                              52.19                                                  Powdered colloidal      0.849                                                 Silicon dioxide.sup.(2)                                                       (Cabosil M-5)                                                                 Powdered colloidal      0.66                                                  Silicon dioxide.sup.(2)                                                       (Cabosil N 70TS)                                                              An elastomeric styrene/ethylene/                                                                      9.97                                                  butylene/styrene                                                              block copolymer                                                               (Kraton G 1652).sup.(3)                                                       A rubber tackifier      5.35                                                  (Piccotac B-BHT)                                                              Tinuvin - P.sup.(5)     0.0179                                                Irganox--1010.sup.(6)   .0.0179                                               Glass bubbles (B23/500).sup.(7)                                                                       1.707                                                 1,1,1 Trichloroethane  20.36                                                  Acryloid B-48-S.sup.(8)                                                                               8.88                                                  ______________________________________                                    

The formulations as set forth above are available commercially as setforth hereinbelow.

(1) The solvent mixture includes 1,1,1 Trichloroethane. VMP Naptha, andmethylene chloride in the ratio of 50/19/7 by weight.

(2) The silicon dioxide fillers, a particulate colloidal or powderedsilicon dioxide, sold under the code name "Cabosil M-5" and "Cabosil N70-TS", are supplied by the Cabot Corp. of Tuscola, Ill.

(3) A styrene/ethylene/butylene/styrene block copolymer sold under thecode name "Kraton G 1652", supplied by Shell Chemical Co.

(4) Piccotac B-BHT is a rubber tackifier sold by Pennsylvania IndustrialChemical Corp. of Chairton, Pa.

(5) Tinuvin-P is an ultraviolet stabilizer sold by the Geigy ChemicalCorp. of Yonkers, N.Y.

(6) Irganox-1010 is an antioxidant sold by the Geigy Chemical Corp. ofYonkers, N.Y.

(7) Glass bubbles (B23/500) are part of a unique series of microspheres,with an average size of less than 70 microns, sold by the 3M Company,St. Paul, Minn.

(8) A solvent solution of methylmethacrylate copolymer in 45% solutionin 54:1 ratio of toluene and 2-methoxyethanol sold under the code name"Acryloid B-48-S", sold by the Rohm & Haas Company.

EXAMPLE 2

A fluorescent pigmented anti-slip coating composition, as follows:

    ______________________________________                                        Material               Parts by Weight                                        ______________________________________                                        Solvent mixture.sup.(1)                                                                              52.48                                                  Powdered colloidal      0.066                                                 Silicon dioxide.sup.(2)                                                       (Cabosil M-5)                                                                 Powdered colloidal      0.67                                                  Silicon dioxide.sup.(2)                                                       (Cabosil N 70TS)                                                              A styrene/ethylene/butylene/styrene                                                                   7.78                                                  block copolymer                                                               (Kraton G 1652 (Shell)).sup.(3)                                               A rubber tackifier      4.16                                                  (Piccotac B-BHT).sup.(4)                                                      Tinuvin - P.sup.(5)     0.014                                                 Irganox-1010.sup.(6)    .0.014                                                Glass bubbles (B23/500).sup.(7)                                                                       2.655                                                 Acryloid B-48-S.sup.(8)                                                                               8.99                                                  1,1,1 Trichloroethane  20.23                                                  Fluorescent Pink Pigment.sup.(9)                                                                      2.25                                                  ______________________________________                                    

The pigmentation is available commercially as follows:

(9) Fluorescent Aurora Pink A-11, sold by Day-Glo Color Corp.,Cleveland, Ohio. (Solid solution of fluorescent dyes inmelamine-sulfonamide formaldehyde resin.)

EXAMPLE 3

A yellow colored anti-slip coating composition, as follows:

    ______________________________________                                        Material                 Parts by Weight                                      ______________________________________                                        Solvent mixture.sup.(1)  77.31                                                Powdered colloidal        0.954                                               Silicon dioxide.sup.(2)                                                       (Cabosil M-5)                                                                 A styrene/ethylene/butylene/styrene                                                                    11.08                                                block copolymer                                                               (Kraton G 1652).sup.(3)                                                       A rubber tackifier        6.01                                                (Piccotac B-BHT).sup.(4)                                                      Tinuvin - P.sup.(5)       0.02                                                Irganox-1010.sup.(6)      .0.02                                               Glass bubbles (B23/500).sup.(7)                                                                         3.84                                                L/F Light yellow (824-000-2511).sup.(10)                                                                0.383                                               Titanium dioxide-Rutele (823-000-0082).sup.(10)                                                         0.383                                               ______________________________________                                    

(10) GPD (General Purpose Dispersions) sold by Nuodex Inc. of Lockland,Ohio.

The surfaces treated with the formulations set forth in Examples 1-3hereinabove provide dried coatings having unusual and effectiveanti-slip and/or gripping action. Water-wet surfaces achieve and retaintheir characteristic, and as such, are extremely desirable for use onwater-wet surfaces, including surfaces of surfboards and wind surfingboards which are used in a variety of diverse conditions.

While the above examples provide specific components within specificquantities, the following table is given for purposes of providingranges of the significant components.

                  TABLE 1                                                         ______________________________________                                        Material In Dried Coating                                                                          Parts by Weight                                          ______________________________________                                        The elastomeric styrene/ethylene/                                                                  30-60                                                    butylene/styrene block copolymer                                              Silicon dioxide (Cabosil M-5)                                                                      3-10                                                     Glass bubbles (B23/500)                                                                            5-15                                                     Rubber tackifier     5-15                                                     Methylmethacrylate   15-25                                                    ______________________________________                                    

The elastomeric styrene/ethylene/butylene/styrene block copolymercomponent is, as previously indicated, commercially available. Thesematerials are prepared by copolymerizing styrene with either butadieneor with isoprene to yield an ABA block copolymer. The specificelastomeric block copolymer listed in Examples 1-3 is obtained byreducing with hydrogen to eliminate most of the ethylenic unsaturationwhich occurs in the butadiene blocks. Thusly treated, the material hasbeen found to be more resistant to the effects of exposure to oxygen aswell as ultraviolet radiation. On the other hand, these block copolymerswhich have not been treated to eliminate most of the ethylenicunsaturation may still be employed, the difference being that somewhathigher levels of stabilizers may be required.

EXAMPLE 4

A seal-coat containing glass bubbles for use in spray application onfoams, as follows:

    ______________________________________                                        Material               Parts by Weight                                        ______________________________________                                        Solvent mixture.sup.(1)                                                                              56.38                                                  Silicon dioxide.sup.(2)                                                                               0.88                                                  (Cabosil M-5)                                                                 A styrene/ethylene/butylene/styrene                                                                  10.64                                                  block copolymer                                                               (Kraton G 1652 (Shell)).sup.(3)                                               A rubber tackifier      3.85                                                  (Piccotac B-BHT)                                                              Tinuvin - P.sup.(5)     0.018                                                 Irganox-1010.sup.(6)    .0.018                                                Methylethyl ketone      8.49                                                  1,1,1 Trichloroethane  17.42                                                  Glass bubbles (B23/500).sup.(7)                                                                       2.29                                                  ______________________________________                                    

Each of the coating formulations set forth hereinabove provide acombination of coating flexibility, surface roughness, along with goodadhesion to the surface to which the coatings are applied. For example,surfboards and wind surfing equipment employ fiberglass reinforcedstyrene-polyester resins and the like. The formulations of the presentinvention have been shown to be non-moisture sensitive, and stable uponextended exposure to ultraviolet light and/or intense sunlight. Thus,the coatings of the present invention may be utilized under adverse andhostile weather conditions and/or environmental-ambient conditions.Certain of them have application to foam structures as well.

The ingredients which are dissolved in the solvent blend provide adesirable film forming system which is stable in the presence of theenvironments in which the product is used. Insoluble fillers, includingthe silicon dioxide and glass bubbles are dispersed in the viscoussolution, and provide physical stability for the cured films.

In certain instances, it is desirable to provide a film which isgenerally transparent, and thus with only limited opacity. This propertyis particularly desired by certain end users who wish to preserve thecolorful designs which may appear on the surface being quoted, such assurfboards. When the glass bubble ingredient is present in limitedquantities, the compositions limit their ability to opacify due toscattering of incident light.

With further attention being directed to the glass bubbles employed inthe coating, these particles by nature of their spherical configurationand microscopic size provide flowability along with the surfaceroughness and/or coarseness, and further facilitate utilization of thecoatings by spray and/or aerosol application techniques. Since thedensity of the microspheres is in the range of 0.23 grams per cc, theindividual spheres tend to float to the surface of the wet coating so asto form a micro-roughness which in combination with the elastomericnature of the binder system is believed to contribute to the improvementin the anti-slip and frictional characteristics. Furthermore, the highisostatic compressive strength of about 500 pounds per square inch alsocontributes to the durability of the coating when subjected to repeateduse. The 70 micron average size of the spheres contributes, asindicated, to the utility of sprayable coatings with minimal clogging ofthe spray nozzles typically utilized.

The examples set forth as Examples 1 and 2 illustrate coatingformulations which, when applied to surfboards and wind surfingequipment, are difficult to remove by peeling of the dried coating. Thecohesive strength of the coatings is reduced by the inclusion and/oraddition of methylmethacrylate copolymers, however this component hasbeen found to increase the adhesive strength. Thus, the dried coatingproduced by the formulation shown in Example 3 has a relatively highcohesive strength but a relatively lower peel strength. If desired, theformulation of Example 3 may be utilized in combination with a primertreatment so as to increase the adhesive strength of the formulation ofExample 3, as well as those shown in Examples 1 and 2.

The various aspects of the present invention as set forth hereinaboveare further defined in the claims hereinbelow, it being noted that thoseskilled in the art may depart from the specific formulations set forthin the examples hereinabove without departing from the spirit and scopeof the present invention.

We claim:
 1. Surface coating formulation for application to surfaces incontact with water for providing surface roughness and for increasingfrictional and anti-slip characteristics of such surfaces while wet,said formulation comprising:(a) a styrene/ethylene/butylene/styreneblock copolymer and contained in said formulation in an amount rangingfrom between about 30 and 60 parts by weight; (b) finely divided silicondioxide filler selected from the group consisting of particulatecolloidal and powdered silicon dioxide and contained in said formulationin an amount ranging from between about 3 and 10 parts by weight; (c)solvent solution of methylmethacrylate copolymer solids and contained insaid formulation in an amount ranging from between about 15 parts and 25parts by weight; (d) rubber tackifier solids and contained in saidformulation in an amount ranging from between about 5 parts and 15 partsby weight; and (e) glass microspheres substantially uniformlydistributed in said formulation and having an average size of up toabout 70 microns, and contained in said formulation in an amount rangingfrom between about 5 parts and 15 parts by weight.
 2. The formulation asset forth in claim 1 wherein said particulate solid filler is selectedfrom the group consisting of particulate solid silicon dioxide and glassmicrospheres having an average size of less than 70 microns.
 3. Surfacecoating formulation for application to surfaces of plastic foamstructures for increasing frictional and anti-slip characteristics ofsuch surfaces, said formulation comprising:(a) asstyrene/ethylene/butylene/styrene block copolymer and contained in saidformulation in an amount ranging from between about 30 and 60 parts byweight; (b) finely divided silicon dioxide filler selected from thegroup consisting of particulate colloidal and powdered silicon dioxideand contained in said formulation in an amount ranging from betweenabout 3 and 10 parts by weight; (c) solvent solution ofmethylmethacrylate copolymer solids and contained in said formulation inan amount ranging from between about 15 and 25 parts by weight; (d)rubber tackifier solids and contained in said formulation in an amountranging from between about 5 and 15 parts by weight; and (e) glassmicrospheres substantially uniformly distributed in said formulation andhaving an average size of up to about 70 microns, and contained in saidformulation in an amount ranging from between about 5 and 15 parts byweight.